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3 years ago

8

On a hot summer day, you need to leave your house for 30 minutes. To use the least amount of energy, should you turn off your ai

r conditioning system, turn up the thermostat, or leave it set at your normal temperature?

1 answer:

Kobotan [32]3 years ago

5 0

Leave it at your normal temperate, if you turn it off it'll take more energy for it to cool off when u get back home.

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A 10.0 cm3 sample of copper has a mass of 89.6

Romashka-Z-Leto [24]

Density is mass divides by volume, so
89.6g / 10cm^3 =8.96g /cm^3

*cm^3 is a standard unit of volume*

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4 years ago

Does the image above correctly illustrate how the coriolis effect impacts global winds?

Sedbober [7]

Yes the winds are moving in a straight line

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3 years ago

Please help me on this position-time graph assignment!!!

saw5 [17]

$\text{Hello there! :)}$

$\text{The velocity is essentially the slope of the graph in a position vs. time graph, so:}$

$\text{Given: From 0 - 8 sec, velocity of 10 m/s.}\\\\\text{From 8 - 18 sec, velocity of -5 m/s. (In opposite direction because of the negative sign)}\\\\\\\text{From 18 - 22 sec, velocity of 0 m/s. (Object at rest)}\\\\\text{From 22 - 24 sec, velocity of 5 m/s.}\\\\\text{Graph the position vs. time graph using the velocities as the slope of the line }$

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4 years ago

A child slides down the water slide at a swimming pool and enters the water at a final speed of 4.22 m/s. At what final speed wo

zheka24 [161]

Answer:

v'=5.97 m/s

Explanation:

If the friction and fluid friction are ignored, then by law of conservation of mechanical energy, potential energy at the top of the slide must be equal to the kinetic energy at the bottom of the slide. Thus, the height of slide and final speed at the bottom of the slide are related as:

$mgh = \frac {1}{2} mv^2\\v =\sqrt{2gh}$

let the final speed be v' when h' = 2 h

$\frac{v'}{v}=\frac{\sqrt h'}{\sqrt h}\\v'=\sqrt{\frac{2h}{h}}\times v\\v'=\sqrt2 v\\v'=5.97 m/s$

8 0

3 years ago

A fish is able to jump vertically out of the water with a speed of 4.45 m/s. What is the speed of the fish as it passes a point

rjkz [21]

Answer:

Explanation:

given

initial velocity u = 4.45m/s

Height = 0.6m

g = 9.8m/s²

Required

final velocity v

Using the equation of motion;

v² = u²-2gH (upward motion of the fish makes g to be negative)

v² = 4.45²-2(9.8)(0.6)

v² = 19.8025-11.76

v² = 8.0425

v = 2.84 m/s

Hence the speed of the fish as it passes a point 0.6 m above the water is 2.84m/s

To get the time, we will use the formula

v = u - gt

2.84 = 4.45 - 9.8t

2.84-4.45 = -9.8t

-1.61 = -9.8t

t = 1.61/9.8

t = 0.164secs

Hence the time taken is 0.164secs

8 0

3 years ago